Morphological observations and rates of protein synthesis in rat muscles incubated in vitro.

Isolated soleus and extensor digitorum longus muscles from small (40 or 70 g) rats developed a central and substantial (13-57%) loss of glycogen and alpha-glucan phosphorylase activity after incubation for up to 2 h in vitro. The central 'core' of the muscles showed a marked decrease in the rate of protein synthesis. It is suggested that during brief periods of incubation the central core of isolated rat muscles becomes hypoxic, and that consequently the viability of such muscles must be in question.